The Diablo and Santa Ana winds will bear down on California, increasing the risk of wildfires

SAN FRANCISCO – A strong “Diablo wind” – notorious for its hot, dry gusts in the fall – is expected to blow across Northern California on Thursday evening, causing a drop in humidity and an increased risk of wildfires.

Meteorologists issued fire warnings through Saturday from the central coast through the San Francisco Bay Area to northern Shasta County, not far from the Oregon border.

According to the National Weather Service, sustained winds of up to 35 miles per hour (56 km/h) are expected in many areas, with gusts of over 65 miles per hour (104 km/h) possible on mountain peaks.

“This could be the most significant wind event so far this year,” said meteorologist Brayden Murdock of the service’s Bay Area office. “We want to tell people to be careful.”

During a Diablo wind, which is common in the fall, the air is so dry that relative humidity drops, vegetation dries out and is ready to burn. The name – “Diablo” is Spanish for “devil” – is used informally for a hot wind that blows inland toward the coast near the San Francisco region as high pressure builds to the west.

Pacific Gas and Electric Co. said it was prepared to shut off power to a small number of customers in areas where strong gusts could damage electrical equipment and start fires.

Targeted power shutdowns were also possible in Southern California, where another notorious weather phenomenon, the Santa Ana winds, is expected on Friday and Saturday.

Winds in the Los Angeles area will not be as strong as in the north, with gusts between 25 and 40 miles per hour (40 and 64 km/h) possible in mountains and foothills, said Mike Wofford, a meteorologist at the weather service's Los office Angeles.

“I think it will be more moderate,” he said on Wednesday. “But the fire risk still exists.”